mSATA SSD Review: Crucial 480GB M500 vs Samsung 1TB 840 EVO

Ever since my purchase of the Samsung Series 9 notebook with its mSATA has constrained my internal storage capacity I have been wanted more capacity to get me past the 600GB I had with the Intel SSD I had put in my previous notebook. In July 2012 reported on my first upgrade – the 256GB Crucial m4 mSATA but this meant I still needed to keep an external hard drive close to hand. In January 2013 Crucial announced that their new M500 SSD would be available in up to 480GB in the mSATA format. However, while it was listed on Amazon UK in April 2013, it did not show up until December. After much deliberation and with some concerns about reports that the M500 ran relatively hot but in the knowledge that the m4 had provided 18 months of trouble-free service, I decided to buy one (£218 from dabs.com).

An mSATA SSD on top of a 2.5” notebook HDD

Samsung announced the 840 EVO mSATA range in December 2013 and, much to my surprise (I wouldn’t have bought the M500 if I knew the EVO mSATA would show up so quickly), some stock reached retailers by the end of January 2014. After further deliberation and soul-searching about whether to wait for the price to drop but with the risk that further stocks might get delayed I concluded that the EVO would give the computer a longer lease of life so I bought it. It cost £510 (from dabs.com) but that price is a bargain compared to the £1013 I paid in 2010 for a 512GB Kingston SSD in 2010. Or wind the clock back further to the £450 it cost in 1995 to have my Toshiba T400 upgraded to 520MB!

The mSATA format was originally announced in January 2010 and is now being superseded by the M.2 (gumstick) format. However, some of the current production of thin-and-light notebooks (and some larger notebooks which include provision for both SATA and mSATA devices) are still using mSATA. There is plenty of potential demand from existing notebook owners who want to upgrade their mSATA storage capacity so there are many potential purchasers who will appreciate competition in the higher capacity mSATA SSD sector.

While this review focuses on two mSATA products, everything except the size is also applicable to the 2.5” versions of these SSDs.

Crucial M500 mSATA SSD Hardware and Software

The Product

The M500 is shipped in a small plastic box similar to that used for memory modules. Crucial include two screws in the package although they weren’t needed because I was doing a replacement. However, they are a thoughtful addition for those people who are buying an SSD to fill an empty mSATA slot in their computer. Crucial did not supply any software with the SSD and the only download offered by the website is the latest firmware (which was already on the SSD).

The Advertised Specifications

Crucial’s advertised specifications for the M500 family show that write speed increases with capacity up to 480GB. According to the data sheet, a 240GB M500 would have similar write performance to the previous m4 SSD but the 480GB M500 should write about 50% faster. The mSATA version of the M500 has the same hardware has other SSDs in the M500 family. Crucial’s support website shows that the same firmware is used by all the M500 family. The M500 uses a Marvell controller chip which has evolved from that used in the m4 SSD. As such, the issues that have occurred with the m4 during the past year should have been flushed out.

Specifications from Crucial’s Data Sheet

Other features not mentioned in this table but available elsewhere are:

Part number: CT480M500SSD3

Marvell 88SS9187 controller

Micron 20 nanometer (nm) MLC NAND Flash

Voltage: 3.3V

Advertised average active power consumption: 150mW

Advertised idle power consumption: <100mW

Weight: <10 grams

Warranty: 3 years

Data according to CrystalDiskInfo

This SSD contains 6 noteworthy chips: The controller, buffer memory and two NAND memory packages are on the top side with a further two memory packages on the bottom. 480 GB in a package not much bigger than a notebook RAM module!

Overall the M500 mSATA looks very similar to the previous m4 SSD but one visible change is the addition of the small orange rectangular components on the bottom of the SSD. These are capacitors designed to hold enough power to enable writing of data in the cache to the NAND memory in the event of a power failure and avoid data corruption or loss in the event of a power failure.

The actual capacity of the NAND memory chips on the SSD is 512GB but the advertised SSD capacity is 480GB. So where has 32GB gone? Some SSD manufacturers use “over-provisioning” which sets aside some of the capacity to help maintain overall performance. SSDs tend to slow down when they are nearly full. Crucial do not state how the unavailable storage capacity is being utilized but it would be reasonable to assume that it is to help maintain long-term performance.

Samsung 840 EVO mSATA Hardware and Software

The Product

Samsung say that their EVO mSATA SSDs use the same technology as the 2.5” EVO SSDs. Samsung were one of the first SSD manufacturers and, probably uniquely, make all the key components that are used in their SSDs. The advertising suggests that the “EVO” name represents evolution (ie progressive development). Samsung have previously manufactured mSATA SSDs including the PM841 which was released in 512GB capacity in January 2013. However, these mSATA SSDs were not officially available in the retail chain whereas the new EVO products are.

The 840 EVO mSATA SSD is shipped in a box large enough to contain the 2.5” version. In addition to the SSD, the box includes a thin, multi-language User Manual and Warranty Statement Summary and two small stickers saying “Samsung SSD activated”. Not included in the box but available to download are Samsung’s SSD Magician software and a data migration utility. The key points in the documentation are:

Avoid strong physical impact which may damage the memory

Avoid letting metal objects contact the SSD because they may cause short circuits

Do not disassemble the product or remove the labels which will void the warranty

The warranty is valid for the shorter of (i) three years and (ii) the date on which the SSD has reached its Total Bytes Written (TBW) threshold as indicated on the data sheet obtainable from Samsung’s SSD website.

However, the currently available data sheet (Rev 1.0) doesn’t mention any TBW values although another part of the Samsung website claims that they tested a 120GB SSD to a TBW of 331TB. I would expect to the 1TB drive to have a proportionately larger TBW threshold although writing even 100TB under normal usage should take a few years (except my SSD is already at 0.96TB after writing about 200GB of files and running some benchmarks – I hope it is the benchmarks that have done the intensive writing). By comparison, Crucial’s advertised endurance for the M500 is 72TBW.

The Advertised Specifications

The 840 EVO SSD family uses Samsung’s 2nd generation 3-bit MLC (often referred to as TLC (triple-level cell) NAND flash memory technology to pack more capacity into the memory chips. Samsung’s ARM-based 3-core MEX controller also runs faster than on the previous generation of SSDs. The EVO SSDs also support encryption.

Specifications from Samsung’s Data Sheet

Overall, the EVO SSD looks very similar to the M500 (no great surprise because they both conform to the same JEDEC specification). Although I didn’t pull the labels off to check, there appears to be six main chips: The controller, buffer memory and two NAND memory packages are on the top side with two further memory packages on the bottom. This 1TB SSD has 1GB of DRAM cache memory.

Data according to CrystalDiskInfo

Samsung’s SSD Magician

SSD Magician is both a utility for monitoring SSD status and a control panel for options including:

Performance Testing and Optimization

Firmware Updating

Operating System Optimization

Secure Erase

RAPID Mode

Data Security

SSD Magician’s Summary Screen

RAPID Mode

Of the various features listed offered by SSD Magician, I will make specific mention of RAPID Mode because it features in the testing. RAPID is short for “Real time Acceleration Processing of I/O Data” does nothing to change the actual performance of the SSD hardware but provides an apparent SSD performance boost by using some system RAM as a cache.

How much RAM does it use? Too much can have a negative impact on overall performance by causing increased use of virtual memory. The RAPID Mode control panel shows a minimum memory requirement of 50MB but also an actual requirement of 115935MB which is implausible because, at over 100GB, it is somewhat more than the system RAM. I therefore used Resource Monitor to look at RAM usage for the same conditions with and without RAPID Mode enabled. This revealed that using RAPID Mode results in an increase in RAM usage of about 580MB which is unlikely to have adverse effects for my NP900X4C with 8GB RAM but might create problems on notebooks with only 4GB RAM (although it is possible that the size of the cache is reduced).

Testing Environment and Methods

Testing of these SSDs involved fitting into my 18 month old Samsung NP900X4C notebook to replace the previous m4 SSD (which had replaced the original Sandisk U100). First in was the M500 onto which installed Windows 7 to get the computer running. The working installation was then cloned onto the Samsung SSD to ensure an identical software environment subject to any optimizations made by the Samsung Magician utility.

Performance

CrystalDiskMark is a popular program for benchmarking SSDs. The results are relatively easy to interpret because there are only four basic tests: Sequential reading and writing; 512k blocks; 4K blocks; and 4K blocks with a queue depth of 32. It is the latter two tests where some SSDs (such as the Sandisk U100 originally supplied in my Samsung notebook) fall down and this weakness isn’t reflected in the manufacturer’s specifications. The QD32 reflects a likely real life workload with several programs trying to use the SSD at the same time.

CrystalDiskMark Results

Crucial M500

840 EVO without RAPID Mode

840 EVO with RAPID Mode

Readers should note that the read speeds of the 840 EVO without RAPID Mode are slightly quicker than the M500. Enabling RAPID Mode boosted the 512K and 4K performance while the 4K QD32 performance reduced (but I should mention that for the first two tests with RAPID Mode the Sequential read also was boosted, to about 900 MB/s, but later tests didn’t replicate this). The write speed results show that the 840 EVO without RAPID Mode is slightly faster than the M500 but RAPID Mode gives a substantial improvement in all tests except QD32 where performance is reduced.

ATTO is another popular SSD benchmark which tests the read and write speeds for a range of data block sizes. The graphical display clearly shows how the speed drops off with the smaller block sizes. This behavior is normal for all SSDs but the extent of the drop off varies. The generally faster write performance of the M500 is visible. The chart also shows clearly that the write speed of smaller block sizes is faster than the read speed. At first glance this appears anomalous but the result is to minimize the drop-off in performance under the queued write situation. The Samsung SSD without RAPID Mode enabled has almost identical read and write speeds but once RAPID Mode is enabled then the results vary widely (but note the maximum value on the graph is over 4GB/s). Repeated tests gave different results, but all very variable. Clearly, this benchmark and RAPID Mode don’t play well together.

ATTO Results

Crucial M500

840 EVO without RAPID Mode

840 EVO with RAPID Mode

A further popular SSD benchmark program is AS-SSD. This also uses four measures of performance and also assigns a score. Enabling RAPID Mode provides a major boost to the 840 EVO results in this benchmark while without RAPID Mode the 840 EVO leads the M500 by about 10%.

AS-SSD Results

Crucial M500

840 EVO without RAPID Mode

840 EVO with RAPID Mode

SiSoftware Sandra is a comprehensive system analysis and benchmarking program with a large database of test results. This enabled me to visually compare the performance of these two SSDs with others I have tested.

SiSoftware Sandra File System Benchmark Results

840 EVO without RAPID Mode

840 EVO with RAPID Mode

I should explain that the light shading on the graphs represents the range of results during each benchmark run while the solid bar shows the average. While Sandra has measured some very high values when RAPID mode is enabled, they only improve the average by less than 5% compared to the non-RAPID measurement.

In order to get a better understanding of SSD performance in a real life situation it is appropriate to look at a more comprehensive benchmarking package which measures the storage performance over a range of different activities chosen to be representative of likely usage. PCMark Vantage is one such benchmark which includes 8 different storage tests to represent a range of work patterns.

PCMark Vantage HDD Benchmark Results

Overall HDD score = 39663

Overall HDD score = 54314

Overall HDD score = 75317

Crucial M500

840 EVO without RAPID Mode

840 EVO with RAPID Mode

The Samsung SSD without the assistance of RAPID Mode scores better than the Crucial in this test with the principal contributor to the good result being the Application Loading component. When RAPID Mode is enabled, the difference becomes greater, primarily due to the Application Loading performance more than doubling. Perversely, however, the overall PC Mark Vantage score with RAPID Mode enabled is slightly lower than without it suggesting that the overall benefit of RAPID Mode depends on the overall usage pattern and whether enhanced storage access gives more benefit than increased competition for CPU and memory resources.

I also repeated the tests on the 840 EVO with RAPID Mode enabled to see the extent of variability and whether they improved with time. All the scores were within 2% of the average and there was no obvious pattern to the variability.

Power Consumption

Early users of the M500 SSDs reported that they could get sufficiently hot that performance started to throttle (a threshold of 70°C is indicated in the documentation) so I was particularly interested to see whether this issue had been fixed by firmware updates. I have no direct way of measuring the SSD power consumption so my testing comprised (i) comparing the overall power usage of the computer (running on battery with HWiNFO monitoring the power drain) under the same operating conditions with each SSD; and (ii) observing the SSD temperatures (more power results in more heat).

The specific operating condition of the computer was to reboot and run on idle with minimum display brightness and wireless devices turned off. The power drain was monitored over 15 minutes to give the system plenty of time to stabilise. Both manufacturers indicate an SSD idle power consumption of less than 0.1W. The load temperature was the maximum observed during the CrystalDiskMark benchmark which provides several minutes of intensive SSD workload. SSD temperatures will be influenced by the environment in the computer, which was the same for these tests.

System Power Consumption and SSD Temperatures

SSD

Average Power

Minimum Power

Idle Temperature

Load Temperature

Crucial M500

6.23W

5.94W

37°C

54°C

Samsung 840 EVO

5.58W

5.16W

28°C

44°C

Difference

0.65W

0.78W

9°C

10°C

These results clearly show that the 840 EVO uses less power and runs cooler although I did not observe the M500 reaching temperatures approaching the throttling point. The 840 EVO also incorporates thermal protection although it appears less likely that this would be triggered under normal usage. It appears that my operating conditions were unable to replicate Crucial’s published idle power consumption of <100mW since the system idle power with the M500 is about 0.7W higher than for the Samsung SSD. This is very significant for users of low power notebooks where the use of the M500 SSD could reduce the battery operation time by more than 10%.

Conclusion

The Samsung 840 EVO is, overall, the better performer although the margin over the M500 is unlikely to be noticeable in everyday usage. Samsung’s RAPID Mode appears to give a further boost to the disk access performance but this reduces the amount of memory available for other applications. The 840 EVO is also more frugal with power which has to be a key consideration for those who want maximum operating time away from a power socket. The Samsung SSD also has the benefit of the SSD Magician software for user-friendly configuration and supports 256 bit full disk encryption where data security is paramount.

The Crucial M500 is, however, the clear winner on price (based on the 500GB pricing – Samsung has no competition in the 1TB mSATA market segment) and the 840 EVO mSATA range currently has a price premium relative to the 2.5” members of the family which were released a few months previously. In time, however, the price tag of the mSATA range can be expected to converge on the 2.5” equivalents. While the M500 retains its margin on price it will be an attractive option for budget conscious purchasers where power use and additional features are not a primary concern.

I have not, unlike some reviewers, tested either SSD to destruction (I want a few years of service!) so I can’t pass comment on the effects of prolonged heavy usage. Both SSDs have mature firmware based on previous SSDs, so there shouldn’t be any nasty surprises lurking in the background. Samsung’s triple level cell memory is an innovation but I’m sure that they have tested it sufficient to support their longevity claims.